Monopotassium phosphate piezoelectric crystals



Patented Nov. 20, 1951 MONOPOTASSIUM PHOSPHATE PIEZO- ELECTRIC CRYSTALSMarie Bruzau and Charles Meuleau, Paris, France, assignors toInternational Standard Electric Corporation, New York, N. Y., acorporation of Delaware No Drawing. Application November 22, 1948,Serial No. 61,521. In France November 21, 1947 (Granted under theprovisions of sec. 14, act of March 2, 1927; 357 0. G.

2 Claims.

The present invention relates to improvements to the patent applicationfiled July 23, 1947, Serial No. 763,164, entitled Piezo-ElectricCrystals, by Marie Bruzau.

In the above mentioned application, a process is described relating to amethod for artificial piezo-electric crystals by adding to asupersaturated crystal solution a substance which facilitates theformation of large crystals from suspended germ crystals. The additionof potassium borate to a solution of potassium phosphate was mentionedin particular.

According to features of the present invention, two substances are addedto the crystal solution, namely potassium borate and potash forsolutions of potassium phosphate, urea and ammonia for solutions ofammonium phosphate.

The crystals obtained according to the process of the invention canreach large dimensions, also growing larger in the transverse direction.

The above mentioned and other features and objects of this inventionwill become more apparent and the invention itself, though notnecessarily defined by said features and object, will be best understoodby reference to the following description of embodiment of theinvention.

As a first example for obtaining ammonium phosphate crystals inaccordance with the invention, the following'proportions have been foundto give favorable results:

Distilled water liters 21 Ammonium phosphate kgs 15 Ammonia 22. Beaum1iters 1 Urea rams 50 tion has been used for obtaining large potassiumphosphate crystals:

Distilled water liters 24 Monopotassium phosphate kgs 12 Caustic potashkg 0.200 Potassium borate kg 0.120

In this case and with the process mentioned in the above mentionedpatent application, the transversal increase in size reached about /20of the increase lengthwise. It is clear that the proportions given abovemay be varied to some extent Without substantially affecting the resultsachieved by the invention and without departing from the scope thereof.

While we have described particular embodiments of our invention forpurposes of illustration, it should be understood that variousmodifications and adaptations thereof may be made within the spirit ofthe invention as set forth in the appended claims.

What we claim is:

1. A process for obtaining a large crystal of mono-potassium phosphateconsisting in suspending a germ crystal in a supersaturated solution ofmono-potassium phosphate and adding thereto caustic potash and potassiumborate thereby forming a large crystal on the germ crystal bycrystalization of the solution.

A process for obtaining large crystals of mono-potassium phosphate as inclaim 1 in which the quantity of caustic potash added is approximately0.200 kg. and the quantity of potassium borate 0.120 kg. for a solutionof 12 kgs. of

mono-potassium phosphate.

MARIE BRUZAU.

CHARLES MEULEAU.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,35 ,571 Dreibrodt -Sept. 21,1920 1,759,152 Booth May 20, 1930 2,459,869 Christensen Jan. 25, 19492,484,829 Holden Oct. 18, 1949

1. A PROCESS FOR OBTAINING A LARGE CRYSTAL OF MONO-POTASSIUM PHOSPHATECONSISTING IN SUSPENDING A GERM CRYSTAL IN A SUPERSATURATED SOLUTION OFMONO-POTASSIUM PHOSPHATE AND ADDING THERETO CAUSTIC POTASH AND POTASSIUMBORATE THEREBY FORMING A LARGE CRYSTAL ON THE GERM CRYSTAL BYCRYSTALLIZATION OF THE SOLUTION.